Where to start in blender?
best is to pick up a real project. or find a tutorial that guides you to model, texture and render a real project. And here some more ideas:

http://www.blenderguru.com/articles/how-i-learned-blender-and-5-tips-for-you/

http://www.blenderguru.com/articles/5-ways-to-make-money-with-blender/

so if your next question on Blender Stackexchange is about a specific problem then you have started ;)